1. Field of the Invention
This invention relates to centralizing devices for use down-well.
2. Summary of the Prior Art
In down-well operations in the oil and gas production industries, it is frequently a requirement that a tool, such as a location sensor, shall be accurately centralized within the casing pipe and this has become even more important in the case of location sensors which in themselves now have an exceptionally high accuracy. Such high accuracy is of little value if the precise location becomes indeterminate because of a non-central location of the sensor within the casing pipe.
Again, the precision of centralization becomes far more important in directional drilling which may involve directions from vertical substantially to horizontal in the same casing pipe, and it has been found that known centralizers are not successful at maintaining centralization, particularly in substantially horizontal bore holes. Furthermore, some sensing units have a considerable length and may weigh over 100 kg.
The amount of support required for such sensing units as a horizontal orientation is approached can be substantial and this support must be provided irrespective of the angular location of the sensing unit relative to the casing pipe.
One object of the present inventin is to provide a centralizing device which enables precise centralizing under all operational orientations.